1. Field of the Invention
The present invention relates to a mobile communications system and, in particular to a mobile communication apparatus having a transmission inhibition function.
2. Description of the Prior Art
With the wide use of high-tech gear such as computers and digital devices having microprocessors therein, there has been a growth in the case where operations of the high-tech gear are adversely affected by radio waves emitted from radio communication equipment such as mobile telephone terminals. Especially, in the case of hospital, it may be a serious problem.
As another example, in the case where assigned frequency bands vary from nation to nation in a region having the borders of a plurality of nations such as Europe, it is unlawful to transmit a radio signal within a different nation.
To prevent undesirable and illegal transmission as described above, there have been proposed several mobile communications systems and mobile terminals having a capability of inhibiting radio transmission.
In Japanese Patent Unexamined Publication No. 5-344050, a mobile communication apparatus is provided with a database storing transmission permitted areas and a location detector using a satellite communication system such as GPS (Global Positioning System). When it is located out of transmission permitted areas, the transmission operation is inhibited.
However, the mobile communication apparatus is not suitable for location detection of a relatively small area such as building location. Further, the mobile communication apparatus needs a GPS device as the location detector.
In a mobile communication system as disclosed in Japanese Patent Unexamined Publication No. 7-87568, a mobile terminal is provided with a database storing transmission and reception inhibition areas and a location detector using GPS. When the mobile terminal is located within a reception inhibition area, the system transmits a signal to the mobile terminal and thereby an audible alert is inhibited. As another system, a system side including base stations and a control center is provided with the database storing transmission and reception inhibition areas and the location detector. When the mobile terminal is located within a transmission inhibition area, the system side informs a user that the user is located in a transmission inhibition area and then the transmission operation is inhibited.
However, the system needs to transmit a message signal to the mobile terminal so as to inform the user of transmission or reception inhibition area. Further, the mobile terminal also needs a GPS device as the location detector.